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  1. #31

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    Quote Originally Posted by water worx View Post
    I think your accel pump is not working...
    Accelerator pumps on both carb racks verified working while off the motor.

  2. #32
    Tool Bag water worx's Avatar
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    I still think you are lean....does it bog when applied throttle ??

  3. #33
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    Just to rule it out, are you sure the arms/levers from N&S to spring are sitting nice and flush with the carb body? (measured w a razor blade across top where spring sits)

  4. #34

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    Pop Off Too Low on Stock 1200 PV (66V)?

    Quote Originally Posted by water worx View Post
    I still think you are lean....does it bog when applied throttle ??
    Not sure what would cause me to be lean. I'm running the settings you suggested. Maybe I should put the 95 pilot jets back in? Over on the YamahaJetBoaters forum, it's common in the XR1800s to have stock carbs, except swap the 87.5 pilots for 95 ones. Consensus is that it helps keep the XR from from bogging. That's why I had the 95 jets to begin with.

    When given throttle, it sort of bogs down, then clears up and just takes off.

    I think the next step is to let each motor idle with the air box off, and see if fuel is dribbling out of the high speed venturis.

    Any other ideas?


  5. #35

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    Quote Originally Posted by jeffg426690 View Post
    Just to rule it out, are you sure the arms/levers from N&S to spring are sitting nice and flush with the carb body? (measured w a razor blade across top where spring sits)
    Yes. On all carbs.

  6. #36
    Tool Bag water worx's Avatar
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    Quote Originally Posted by Robb235 View Post
    Not sure what would cause me to be lean. I'm running the settings you suggested. Maybe I should put the 95 pilot jets back in? Over on the YamahaJetBoaters forum, it's common in the XR1800s to have stock carbs, except swap the 87.5 pilots for 95 ones. Consensus is that it helps keep the XR from from bogging. That's why I had the 95 jets to begin with.

    When given throttle, it sort of bogs down, then clears up and just takes off.

    I think the next step is to let each motor idle with the air box off, and see if fuel is dribbling out of the high speed venturis.

    Any other ideas?
    Open lows .5 turn & see if it gets better.

  7. #37
    Tool Bag water worx's Avatar
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    Update....We got a 2001 XR1800 in today that had filled with water due to owner forgetting to put drain plug in. Had to pull the carbs to get water out & rebuild.

    Put 115 springs in & really didnt care for how it came out off the bottom so I put some 95 gram springs in & BAM this thing is a beast !! Comes out hard from a dead idle & performs so much better & starts a lot easier.

    Stock jetting with accel pump 1.2 N/S 95 gram springs 1 3/4 turn on the low screws & 1 1/2 turns on the high screws.

  8. #38

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    Pop Off Too Low on Stock 1200 PV (66V)?

    Did you try idling it for an extended time and then going WOT? The arm spring doesn't affect starting?

  9. #39
    Tool Bag water worx's Avatar
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    A couple minutes tops.

    You also have to remember that after extended idiling the waterbox gets filled with water & has to "push" out in order to get clean acceleration.

    But overall it works a lot better than 115 springs. It helps starting due to lower pop off pressure.

  10. #40

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    Pop Off Too Low on Stock 1200 PV (66V)?

    Quote Originally Posted by water worx View Post
    A couple minutes tops.

    You also have to remember that after extended idiling the waterbox gets filled with water & has to "push" out in order to get clean acceleration.

    But overall it works a lot better than 115 springs. It helps starting due to lower pop off pressure.
    Good deal. Like I mentioned earlier, common consensus on the jetboat board I frequent is to swap out the 87.5 low speed jets for 95 jets to richen up the bottom end. Since you kept the stock 87.5 pilot jets, you achieved the same thing by lowering pop-off. The low speed jets and pop off overlap; pilot jets affect off idle to 1/3 throttle, and pop affects off idle to 1/4 throttle. Curious how that boat would run if you put 115g springs back in, along with 95 pilot jets.

    I just got home from traveling for work, and it's raining here. Doesn't look like I'll be able to water test since it's supposed to rain and storm all weekend. I'm traveling again the first part of next week, so looks like it won't be until end of next week before I can get the boat in the water.

    Click image for larger version. 

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